This test allows the evaluation of the child's capacity to fuse into a single image, the images formed individually by each eye. The level of coordination between the eyes can be determined through a series of functional stereoscopic testing which is duly adapted according to patients' age.
Quite frequently, the alteration of the binocular vision (or difference in image quality between the two eyes) causes the child to deviate one of his/her eyes, thus developing a condition known as "lazy eye" and/or loss of depth perception.